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Zachary Amsden f2f30ebca6 [PATCH] x86: introduce a write acessor for updating the current LDT 
Introduce a write acessor for updating the current LDT.  This is required
for hypervisors like Xen that do not allow LDT pages to be directly
written.

Testing - here's a fun little LDT test that can be trivially modified to
test limits as well.

/*
 * Copyright (c) 2005, Zachary Amsden (zach@vmware.com)
 * This is licensed under the GPL.
 */

#include <stdio.h>
#include <signal.h>
#include <asm/ldt.h>
#include <asm/segment.h>
#include <sys/types.h>
#include <unistd.h>
#include <sys/mman.h>
#define __KERNEL__
#include <asm/page.h>

void main(void)
{
        struct user_desc desc;
        char *code;
        unsigned long long tsc;

        code = (char *)mmap(0, 8192, PROT_EXEC|PROT_READ|PROT_WRITE,
                                 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
        desc.entry_number = 0;
        desc.base_addr = code;
        desc.limit = 1;
        desc.seg_32bit = 1;
        desc.contents = MODIFY_LDT_CONTENTS_CODE;
        desc.read_exec_only = 0;
        desc.limit_in_pages = 1;
        desc.seg_not_present = 0;
        desc.useable = 1;
        if (modify_ldt(1, &desc, sizeof(desc)) != 0) {
                perror("modify_ldt");
        }
        printf("code base is 0x%08x\n", (unsigned)code);
        code[0x0ffe] = 0x0f;  /* rdtsc */
        code[0x0fff] = 0x31;
        code[0x1000] = 0xcb;  /* lret */
        __asm__ __volatile("lcall $7,$0xffe" : "=A" (tsc));
        printf("TSC is 0x%016llx\n", tsc);
}

Signed-off-by: Zachary Amsden <zach@vmware.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
 		2005-09-05 00:06:13 -07:00
..
acpi /home/lenb/src/to-linus branch 'acpi-2.6.12' 2005-07-29 23:31:17 -04:00
asm-alpha [PATCH] sab: consolidate kmem_bufctl_t 2005-09-05 00:05:48 -07:00
asm-arm [PATCH] sab: consolidate kmem_bufctl_t 2005-09-05 00:05:48 -07:00
asm-arm26 [PATCH] sab: consolidate kmem_bufctl_t 2005-09-05 00:05:48 -07:00
asm-cris [PATCH] sab: consolidate kmem_bufctl_t 2005-09-05 00:05:48 -07:00
asm-frv [PATCH] sab: consolidate kmem_bufctl_t 2005-09-05 00:05:48 -07:00
asm-generic [PATCH] x86: ptep_clear optimization 2005-09-05 00:05:48 -07:00
asm-h8300 [PATCH] sab: consolidate kmem_bufctl_t 2005-09-05 00:05:48 -07:00
asm-i386 [PATCH] x86: introduce a write acessor for updating the current LDT 2005-09-05 00:06:13 -07:00
asm-ia64 [PATCH] sab: consolidate kmem_bufctl_t 2005-09-05 00:05:48 -07:00
asm-m32r [PATCH] sab: consolidate kmem_bufctl_t 2005-09-05 00:05:48 -07:00
asm-m68k [PATCH] sab: consolidate kmem_bufctl_t 2005-09-05 00:05:48 -07:00
asm-m68knommu [PATCH] mm: consolidate get_order 2005-09-05 00:05:39 -07:00
asm-mips [PATCH] mips: remove timex.h for vr41xx 2005-09-05 00:06:08 -07:00
asm-parisc [PATCH] sab: consolidate kmem_bufctl_t 2005-09-05 00:05:48 -07:00
asm-powerpc [PATCH] Move all the very similar files to asm-powerpc 2005-08-30 13:32:06 +10:00
asm-ppc [PATCH] ppc32: mv64x60 updates & enhancements 2005-09-05 00:06:00 -07:00
asm-ppc64 [PATCH] ppc64: Add VMX save flag to VPA 2005-09-05 00:06:01 -07:00
asm-s390 [PATCH] sab: consolidate kmem_bufctl_t 2005-09-05 00:05:48 -07:00
asm-sh [PATCH] sab: consolidate kmem_bufctl_t 2005-09-05 00:05:48 -07:00
asm-sh64 [PATCH] sab: consolidate kmem_bufctl_t 2005-09-05 00:05:48 -07:00
asm-sparc [PATCH] sab: consolidate kmem_bufctl_t 2005-09-05 00:05:48 -07:00
asm-sparc64 [PATCH] sab: consolidate kmem_bufctl_t 2005-09-05 00:05:48 -07:00
asm-um [PATCH] mm: correct _PAGE_FILE comment 2005-09-05 00:05:45 -07:00
asm-v850 [PATCH] sab: consolidate kmem_bufctl_t 2005-09-05 00:05:48 -07:00
asm-x86_64 [PATCH] i386: cleanup serialize msr 2005-09-05 00:06:11 -07:00
asm-xtensa [PATCH] sab: consolidate kmem_bufctl_t 2005-09-05 00:05:48 -07:00
linux [PATCH] x86: fix EFI memory map parsing 2005-09-05 00:06:09 -07:00
math-emu Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
media [PATCH] V4L: Miscellaneous fixes 2005-08-01 19:13:59 -07:00
mtd [MTD] NAND: Honour autoplacement schemes supplied by the caller 2005-05-23 13:20:45 +02:00
net /spare/repo/netdev-2.6 branch 'master' 2005-09-01 18:02:01 -04:00
pcmcia [PATCH] pcmcia: fix pcmcia-cs compilation 2005-07-12 16:00:59 -07:00
rdma [PATCH] IB: move include files to include/rdma 2005-08-26 20:37:38 -07:00
rxrpc Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
scsi [SCSI] fix target scanning oops with fc transport class 2005-08-08 17:14:55 -05:00
sound [ALSA] version 1.0.10rc1 2005-08-30 08:48:35 +02:00
video [PATCH] DEC PMAGB B framebuffer update 2005-09-05 00:06:03 -07:00